Abstract: A vehicle auxiliary electric-power-supplying system can normally stop an electric power inverter by the frequency in use for an electric power supplier being suppressed as low as possible, and electric power being immediately started to be supplied from the power supplier to a controller in a case in which normal electric power has become unable to be obtained from power-outputting of the electric power inverter.

Abstract: An electronic device may be provided with more than one industry-standard type of AC power connector. The electronic device may be powered in any of a variety of locations by selectively exposing one of the power connectors selected according to an AC power outlet available at that location. A location-specific power cord may be used to connect the exposed power connector to the AC power outlet. The location-specific power cord may have, for example, a line socket at one end of a type that matches the exposed power connector, and a power plug at the other end of a type that matches the AC power outlet at the location. Predefined power settings appropriate for use with the AC power outlet and the exposed power connector may be automatically invoked.

Abstract: Systems and methods are provided for an on-demand boost converter for use in a vehicle. An automotive drive system comprises a boost converter having an input node, a first output node associated with a first boost leg, and a second output node associated with a second boost leg. A fuel cell is coupled to the input node of the boost converter and a battery is coupled to the first output node. An inverter module is coupled to the second output node, and a vehicle traction drive unit is coupled the inverter module. A first switch is coupled between the second output node and the first output node, wherein the battery provides energy to the second output node when the first switch is closed.

Abstract: A device for converting an electric current includes at least one phase module having an AC terminal and at least one DC terminal. Phase module branches, each of which is equipped with serially connected submodules, are respectively provided between each DC terminal and each AC terminal. Each submodule is provided with at least one power semiconductor. Semiconductor protecting means are connected in parallel or in series to at least one of the power semiconductors to enable the device to withstand even high short-circuit currents for a sufficient period of time. A method for protecting the power semiconductors of the device, is also provided.

Abstract: A load compensation circuit for a switching regulator including a comparator circuit and an adjustable voltage source. The switching regulator includes a switch circuit for converting an input voltage to a regulated output voltage and for driving a load current, and a controlled switch driver circuit having a supply voltage input and an output driving the switch circuit. The comparator circuit senses the load current and adjusts a voltage control signal to adjust switching efficiency based on the load current. The voltage source has an input receiving the voltage control signal and an output for providing a switch supply voltage to the supply voltage input of the switch driver circuit, where the voltage source adjusts the switch supply voltage based on the voltage control signal. A method of compensating a switching regulator based on load including sensing load current and adjusting the switch supply voltage to adjust switching efficiency.

Abstract: A method is provided for connecting a 110 V genset to a transfer switch feeding a 220 V service entrance such that all 220 V loads are automatically blocked out and all 110 V circuits are accessed. The method includes wiring of the genset to the transfer switch such that the two hot 220 V terminals on the genset entrance side of the transfer switch are connected together and wired to the hot 110 V side of the genset. The neutral lead of the transfer switch is connected to the neutral side of the genset, as per normal practice.

Abstract: A gaming control board having low-power circuitry and high-power circuitry for controlling the operation of a gaming machine. The low-power circuitry includes logic components including a CPU that executes instructions for randomly selecting a plurality of game outcomes in response to wagers inputted by a player. The high-power circuitry includes high-power components such as lamp drivers for interfacing high-power signals between the gaming control board and a game interface board. Two connectors are provided on the gaming control board, one to interface low-power signals and another to interface high-power signals. The high-power circuitry is located near the connector interfacing the high-power signals for optimal EMI suppression.

Abstract: A controller for a multi-level converter regulates the DC midpoint voltage of the multi-level converter by accounting, for the effect non-redundant switch states have on the DC midpoint current. The controller includes a DC bus regulator that monitors the DC output voltage and generates in response a commanded voltage vector. The duty cycle calculator is operably connected to receive the commanded voltage vector generated by the DC-bus regulator and to generate in response to the commanded voltage vector duty cycles associated with non-redundant switch states. The DC midpoint regulator is operably connected to receive the non-redundant duty cycles calculated by the duty cycle calculator and to generate in response a first midpoint current command that accounts for the effect the non-redundant switch states have on the midpoint current.

Abstract: A signal processing system having different power domains is provided. The signal processing system has a first amplifier circuit operating under a first power domain; a second amplifier circuit operating under a second power domain and having a feedback configuration; a first impedance unit, coupled between an output node of the first amplifier circuit and a first input node of the second amplifier circuit; and a bias current generating circuit, coupled to the first input node of the second amplifier circuit, for providing a bias current to thereby reduce a DC current flowing through a feedback path of the second amplifier unit.

Abstract: A power conversion apparatus includes a first single-phase inverter that uses as a DC power source a first DC voltage that is boosted from a solar light voltage by a boosting chopper circuit. The first single-phase inverter is arranged between two single-phase inverters that use second DC power sources that are supplied from the first DC power source. AC sides of the respective single-phase inverters are connected in series. A power conditioner thus configured provides an output voltage using the sum of the generated voltages of the respective single-phase inverters. Chopper circuits are connected between the first DC power source and the second DC power sources, and power is supplied to the second DC power sources from the first DC power source via switching devices in the single-phase inverters.

Abstract: An electric power conversion apparatus includes a power converter connected to at least a first DC voltage source, a second DC voltage source and an AC electric motor. A control unit controls the power converter to generate a first PWM pulse train for supplying a first output voltage pulse train from the first DC voltage source to the AC electric motor and a second PWM pulse train for supplying a second output voltage pulse train from the second DC voltage source to the load in such a manner to form a pulse continuous in time in a final output voltage at least from each pulse of the first output voltage pulse train and a subsequent pulse of the second output voltage pulse train. A current path is provided constantly from the AC electric motor to at least one of the DC voltage sources.

Abstract: A device for contactless electrical power transmission in a system including at least one stationary and one moving part, power being transmitted between the at least one stationary part and the at least one moving part includes an inductive transformer including a primary winding disposed on the stationary part and a secondary winding disposed on the moving part, the inductive transformer bridging an isolating point between the stationary part and the moving part. The device also includes a frequency generator having a series-resonant circuit capacitor connected to the primary winding and at least one actuator control element connected to the secondary winding and including a matrix arrangement of a plurality of switchable power semiconductors. At least portions of the inductive transformer, frequency generator and at least one actuator control element are disposed in an area of a rotor shaft and a rotor head of a rotary-wing aircraft.

Abstract: An automatically switchable dual-power-circuit-loop circuit system selectively supplies a first power source through a first voltage output circuit loop to an output terminal, and a second power source is selectively supplied through a second voltage output circuit loop to the output terminal. A switching control circuit functions to detect the first output voltage of the first voltage output circuit loop. When the first output voltage regularly supplies electrical power, the first power source is supplied through the first voltage output circuit loop to the output terminal, while the switching control circuit generates a switching signal to switch a switching element to an open-circuit condition thereby cutting off the second voltage output circuit loop. When the first power source fails to supply power, the switching element is set in a closed-circuit condition to allow the second power source to be supplied through the second voltage output circuit loop to the output terminal.

Abstract: A constant voltage regulator and registers R1 and R2 generate a reference voltage with at least one of voltages supplied from a battery and an AC adaptor. The reference voltage is supplied to a first input terminal of a comparator. An input voltage supplied from the AC adaptor and divided by registers R3 and R4 is supplied to a second input terminal of the comparator. The comparator compares the reference voltage with the input voltage. When the reference voltage is lower than the input voltage, an FET switch SW1 is turned on and power is supplied from the AC adaptor side. When the reference voltage is higher than the input voltage, an FET switch SW2 is turned on and power is supplied from the battery side.

Abstract: Methods and mechanisms to simultaneously regulate two or more supply voltages provided to an integrated circuit by a voltage regulator. In an embodiment of the invention, a voltage regulation message exchanged between the integrated circuit and the voltage regulator includes an identifier indicating two or more supply voltages selected from a plurality of supply voltages provided to the integrated circuit by the voltage regulator, where the voltage regulation message relates to the indicated two or more supply voltages. In another embodiment, the voltage regulation message indicates a desired supply voltage level to which the indicated two or more supply voltages are to transition.

Abstract: There is provided an electric power supply system in which electric power is delivered from one electric power unit to load or the other electric power unit and can control and monitor the other electric power unit by one electric power unit. An electric source bus is built up by connecting an output line 5 of a DC-DC converter 2 to each of POL converters 6a, 6b, 6c. Loads 7a, 7b are connected to each of outputs of the POL converter 6a, 6b, 6c. An electric power unit 1 delivers electric power to the POL converters 6a, 6b, 6c by means of the DC-DC converter 2 and besides has functions to control and monitor statuses of the POL converters 6a, 6b, 6c. From a high-order system 10, a sequence program 20 and a monitoring program 21 can be rewritten which fulfill the functions of controlling and monitoring.

Abstract: The invention relates to a power supply circuit comprises several power supply modules for supplying power to various sub-assemblies and/or interfaces of electrical equipment, e.g. a communications equipment or a personal computer, in addition to a regulating circuit that regulates a first power supply module. The regulating circuit is connected to the power supply outputs of those power supply modules, between which a maximum voltage differential deviates from a reference value, the first power supply module is corrected in such a way that the deviation is minimized.

Abstract: There is provided a power supply for AC/DC and DC/DC conversion which receives the DC power supplied from airplanes, vehicles and vessels as well as normal AC power, and converts the power to DC power and supplies it to portable electronic products. The power supply for AC/DC and DC/DC conversion includes an AC input 10, a DC input 20, a switch 30 for selecting AC input power or DC input power, a DC output 40, and a circuit used for AC/DC and DC/DC conversion 100 which converts the power input from the AC input or the DC input to DC power having predetermined values of current and voltage, and a secondary side of a transformer (TL) for AC/DC conversion inside the circuit for conversion serves as an inductor for performing DC/DC conversion.

Abstract: A member for measurement of cell voltage and temperature in a battery pack comprises temperature measuring elements (a) attached to the surfaces of unit cells, and a printed circuit board (b) having protrusions formed at the upper end thereof such that the protrusions are connected to electrode lead connection members that connect electrode leads of the unit cells, connection parts formed at the lower part thereof for allowing the temperature measuring elements to be attached to the printed circuit board, and a circuit through which electric current for voltage measurement of the unit cells and electric current for temperature measurement of the temperature measuring elements flow.

Abstract: In a provided power supply unit, a plurality of circuit elements are integrated into a chip, wherein the circuit elements generate one or more output voltages by using an input voltage. Thus, although the number of voltages, which can be generated by the power supply apparatus, is remarkably large, the power supply apparatus can be miniaturized. In addition, an apparatus, in which the power supply apparatus is installed, can be miniaturized.

Abstract: A circuit includes a first and a second input terminals and an output terminal. A first circuital branch is connected between the first input terminal and the output terminal, and a second circuital branch connected between the second input terminal and the output terminal. The first and second circuital branches are selectively activatable for coupling the first input terminal with the output terminal and the second input terminal with the output terminal, respectively. The first and second circuital branches each include at least one electronic device having at least a first and a second device terminals. Each electronic device can of sustain voltage differences across the first and second device terminals that are up-limited in absolute value by a first predetermined maximum value lower than the maximum of absolute values of voltage differences between the output terminal and the first input terminal, and between the output terminal and the second input terminal, respectively.

Abstract: A description is given of a method for charge reversal of a circuit part of an integrated circuit from a first electrical potential to a second electrical potential of a first voltage network. In this case, the circuit part is connected to the first voltage network for charge reversal. Furthermore, the circuit part is connected to a second voltage network for charge reversal, said second voltage network providing a third electrical potential between the first and the second electrical potential. The circuit part is automatically isolated from the second voltage network before its electrical potential reaches the second electrical potential.

Abstract: Systems and methods are disclosed for a two-source inverter. The systems and methods combines operation of a first voltage source powering a conventional single source inverter with second voltage source powering a novel switch configuration to power a load. The switch configuration is controlled by a plurality of control signals generated by controller based on a variety of control modes, and feedback signals.

Abstract: A power management system has a primary power source (100) and a secondary power source (106) generated from the primary power source (100) with a power output selector (204) coupled to each for selecting power for a regulated power output (212). First, during initialization and at any other time during operation, when the primary power source (102) exceeds the secondary power source (106), the primary power source (102) is used as a power supply for the regulated power output (212). Second, at any time after initialization that the primary power source (102) exceeds the regulated power output (212), the primary power source (102) is used as the power supply for the regulated power output (212). Third, at any time after initialization that the secondary power source (106) exceeds the primary power source (106) and the primary power source (102) is less than the regulated power output (212), the secondary power source (106) is used as the power supply for the regulated power output (212).

Abstract: A DC/DC power conversion device includes n-stage circuits comprised of an inverter circuit for driving which is connected between positive terminals and negative terminals of smoothing capacitors, and a rectifier circuit which is connected between positive terminals and negative terminals of smoothing capacitors; a first circuit corresponding to at least one among the n-stage circuits and configured by connecting in parallel cell circuits of m, second circuits corresponding to a plurality of remaining circuits of (n?1) among the n-stage circuits; capacitors for energy transfer connected between middle points of the cell circuits and middle points of the second circuits; and column circuits of m comprised of the cell circuits, the second circuits and the capacitors for energy transfer, wherein the middle points are contact points of high voltage sided elements and low voltage sided elements of the cell circuits and the second circuits; and driving signals for driving the respective column circuits have the sam

Abstract: A DC-DC switching cell module includes a switch, a rectifier, an output filter coupled to the rectifier, and an input port for receiving an external PWM control signal from a controller. The switching cell module is configured to control the switch in response to the external PWM control signal to generate a DC output voltage from a DC input voltage. The switching cell module is configured for attachment to a circuit board as a discrete component.

Abstract: A series regulator, which includes a power adjusting portion to which power is supplied, the power adjusting portion making an adjustment to the power thus supplied and outputting the power thus adjusted to a load, and an adjustment control portion detecting an output voltage that is a voltage outputted to the load and controlling the adjustment based on the detection result, is provided with: a current detecting portion for detecting an output current that is a current outputted to the load; and a power supplying section for supplying the power to the power adjusting portion after changing a voltage according to the detection result of the current detecting portion. With this configuration, even when the magnitude of the output current varies, it is possible to appropriately adjust the input voltage according to the variations in the output current.

Abstract: An exemplary multiplexed direct current regulation output circuit (2) includes a feedback circuit (22), a sampling circuit (30), a power control chip (21), a first output (27), a second output (28), a first half wave rectifier circuit (23), a second half wave rectifier circuit (24), a first filter circuit (25), a second filter circuit (26), a transformer (20), and a balance control circuit (29). The transformer is configured to provide low voltages to the first output via the first half wave rectifier circuit and the first filter circuit in series, and provide high voltages to the second output via the second half wave rectifier circuit and the second filter circuit in series. The balance control circuit is configured to control a voltage at the second output.

Abstract: The present invention discloses a power supply apparatus which is an apparatus installed in an electronic system, and the apparatus includes a DC power input transformer connected with a DC voltage adapter through an electric extension cord, such that DC power of different voltage values is rectified into a single voltage value through the DC power input transformer and transmitted to the DC voltage adapter through an electric extension cord, and divided into different voltage outputs by the adapter for supplying different voltages to electronic equipments. The invention not only installs the transformer and the adapter at appropriate spaces depending on the spaces of the electronic system, but also supplies DC power with different voltages to different electronic equipments.

Abstract: Consistent with an aspect of the present disclosure, a method is provided for controlling an AC signal, which is supplied to a load and selectively supplied to a utility grid. In response to a fault in the utility grid, the method includes decoupling the AC signal from the utility grid, and determining whether a voltage associated with the AC signal is within a desired band. The method also includes adjusting the voltage associated with the AC signal when the AC signal is outside the desired band, and comparing a magnitude of a current associated with the AC signal with a desired current value to thereby obtain a comparison result. In response to the comparison result, the current associated with the AC signal is adjusted when the voltage associated with the AC signal is within the desired band.

Abstract: A power supply device that reduces the loss of a load device, such as an amplifier, which is a supply destination of a power supply voltage. The power supply device includes a controller 14 for controlling a power supply voltage supplied to a load device 12 variably in accordance with an input voltage of the load device 12 (output of a signal source 13).

Abstract: A universal power adapter has an input for receiving an input voltage from a power source and an output for supplying an output voltage selected from amongst two or more preset voltages. A voltage converter circuit converts between the input voltage and the two or more preset voltages.

Abstract: An electric power generation system is described can include a variable speed generator and an engine driving the generator to provide an AC electric power output. The output is monitored for different types of transient conditions. For example, electric current of the output is evaluated to identify a first type of transient condition and power factor of the output is evaluated to identify a second type of transient condition. System adjustment is made based on the condition type. In one form, the system is used to provide electricity on board a vehicle such as a motor coach, ship, or the like. In other forms, the system provides electric power to a remote building that does not have access to a public power grid or the system provides back-up power in case of power grid failure or the like.

Abstract: A power supplier with combinable power output ports includes plural power output ports which include at least a unit output port, wherein the unit output port has two terminal slots in which two power terminals at different potentials are respectively mounted, and the unit output port can be combined with another power output port to form a combined output port having another voltage output. The power supplier of the present invention, according to the demands of the user, provides different voltage output standards or sets through combining the unit output port with another unit output port or combining the unit output port with the base level output port to transform into the needed voltage output.

Abstract: A universal interface circuit and an associated method are provided that can supply a computer logic circuit, such as the components mounted upon an adapter card, with first and second inputs having first and second predetermined voltage levels, respectively, based upon power drawn from both first and second supply voltages. The interface circuit typically includes a first power supply circuit for providing the first input having the first predetermined voltage level in response to the first supply voltage. Additionally, the interface surface includes a regulator for generating an output having the second predetermined voltage level in response to the first supply voltage. The interface circuit further includes a second power supply circuit for providing an output that also has the second predetermined voltage level, albeit in response to the second supply voltage.

Abstract: An exemplary multiplexed DC voltage regulation output circuit (2) comprises a first output circuit, a second output circuit, a transformer (21), a power control chip (22), a feedback circuit (20), and a control circuit (26). The first output circuit is configured for outputting low voltage. The second output circuit is configured for outputting high voltage. The transformer is configured for outputting voltages to the first output circuit and the second output circuit. The feedback circuit feeds composite signals from the first output circuit and the second output circuit back to the power control chip. The power control chip adjusts the output voltages of the transformer by changing impulse width of voltages transmitted into the transformer in accordance with the composite signals. The control circuit controls the output voltage of the second output circuit back to a normal high voltage when the output voltage is higher than normal.

Abstract: A power supplying apparatus supplying power to a predetermined system unit is provided with a power selecting unit which is directly connected to the system part, to select one of a plurality of inputs of power and output a selected power to the system unit; and a controller which is provided outside a power supplying path between the power selecting unit and the system unit, to control the power selecting unit to selectively output the power selected by the power selecting unit to the system unit according to a power switching signal.

Abstract: An apparatus and method for controlling a supply voltage of a multiple interface card includes a first voltage adjustment unit, a second voltage adjustment unit, an internal circuit, a first voltage controller, and a second voltage controller. The first voltage controller adjusts a first supply voltage to a first internal supply voltage used as an operating voltage of the internal circuit and supplies the first internal supply voltage to the internal circuit. The second voltage adjustment unit adjusts a second supply voltage to a second internal supply voltage used as an operating voltage of the internal circuit and supplies the second internal supply voltage to the internal circuit. The first voltage controller detects the first supply voltage and, according to the first supply voltage, either applies the first supply voltage to the first voltage adjustment unit or blocks the first supply voltage from the first voltage adjustment unit.

Abstract: Memory interface systems include one or more channel lines that couple a memory to a memory controller such that the channel line(s) are responsive to a terminal voltage that is independent of supply voltages for the memory and the memory controller. Because the memory interface system uses a terminal voltage that is independent of the supply voltages of the memory and the memory controller, the interface system may be unaffected by voltage differences between the memory supply voltage and the memory controller supply voltage.

Abstract: A method of managing power resources for an electrical system of a vehicle may include identifying enabled power sources from among a plurality of power sources in electrical communication with the electrical system and calculating a threshold power value for the enabled power sources. A total power load placed on the electrical system by one or more power consumers may be measured. If the total power load exceeds the threshold power value, then a determination may be made as to whether one or more additional power sources is available from among the plurality of power sources. At least one of the one or more additional power sources may be enabled, if available.

Abstract: A method and apparatus for powering an electronic circuit use comparators of supply voltages and voltage regulators to facilitate powering the electronic circuit utilizing more than one supply voltage. In one embodiment, power supplies of step-up power units are controlled using comparators of step-down power units and the step-up power units temporarily provide power to accidentally disabled of step-down power units.

Abstract: A universal interface circuit and an associated method are provided that can supply a computer logic circuit, such as the components mounted upon an adapter card, with first and second inputs having first and second predetermined voltage levels, respectively, based upon power drawn from both first and second supply voltages. The interface circuit typically includes a first power supply circuit for providing the first input having the first predetermined voltage level in response to the first supply voltage. Additionally, the interface surface includes a regulator for generating an output having the second predetermined voltage level in response to the first supply voltage. The interface circuit further includes a second power supply circuit for providing an output that also has the second predetermined voltage level, albeit in response to the second supply voltage.

Abstract: A method for controlling multiple voltages in a power supply includes providing a plurality of DC to DC power converters. Each power converter includes a pulse width modulator controller having a control pin. The method also includes when a voltage supply to the power controllers reads a particular level. After the particular level is met, the method includes providing a respective rising ramp control signal to each respective control pin of the pulse width modulator controller such that each respective power converter generates desired voltage level over time characteristics.

Abstract: The invention relates to a combined AC-DC to DC converter. The converter provides the option of coupling to an AC supply source with at least one phase and the further option of coupling to at least one DC supply source. The converter obtains supply from at least one supply source at a time; and the converter contains controllable contact means that are, upon switching between supply sources, capable of connecting and disconnecting the individual supply sources to/from the converter, whereby a pulse signal is generated. The converter contains at least one coil that is in connection with at least one DC output.

Abstract: A power supply switching circuit arrangement is configured to provide a relatively smooth (low noise) power supply switch-over during the transition between active and quiescent modes. Complementary inputs of an operational amplifier are selective coupled to feedback paths to the amplifier and the power supply switching circuit arrangement, so as to bias a switching transistor during system active mode at a value that is just slightly below the turn-on voltage of the transistor. This means that turning on the switching transistor for the purpose of providing quiescent mode powering of the utility device requires only a small transition in control voltage from an active mode ‘almost turned-on’ level.

Abstract: A power supply unit (system power supply IC) has a multiplicity of power supply circuits providing for different supply voltages. Should an abnormal condition take place in any of the multiple power supply circuits, the power supply circuit suffering the abnormality issues an abnormality detection signal that contains a power supply circuit number and an abnormality type, which signal is stored in a nonvolatile memory together with time data indicative of the time of reception of the abnormality detection signal before all the power supply circuits are disabled. Thus, this arrangement protects the system power supply IC and the loads connected thereto, and provides convenient means for analyzing the abnormality and replicating it if necessary, based on the abnormal power supply circuit number, abnormality type and time data stored in the nonvolatile memory.

Abstract: A dual input DC—DC power converter integrating high/low voltages can simultaneously or individually transfer the power from two input power sources respectively having voltages higher than and lower than an output voltage to a load end. If one power source is failed, the other power source can still transfer power normally. Moreover, if an appropriate control circuit is matched, the currents and powers of the two input DC power sources can be accurately controlled to accomplish tracking operations of the maximum power of each power source. The power conversion system can be exactly simplified to accomplish the effects of enhanced efficiency and lowered cost and also have the advantage of simultaneous transmission of power from two voltage sources to the load end.

Abstract: A power converter that can be used in a vehicle equipped with an electrical motor provides power to both the electrical motor and other, auxiliary loads, such as a headlamp, that require a different voltage. The power converter includes a first DC power supply that generates a first voltage equivalent to the voltage required by the auxiliary loads and a second DC power supply, connected in series with the first DC power supply, that generates a differential voltage, where the sum of the differential voltage and the first voltage is the voltage required to drive the electrical motor. A DC-DC converter is connected to the second power supply and converts the differential voltage to the voltage required to drive the auxiliary loads.

Abstract: A combination selector switch and infinite switch energy regulator provides a plurality of simmer voltages. An infinite switch energy regulator for adapting input voltage level to an average output voltage level is provided. This energy regulator has a rotatable shaft for adjusting the average output voltage level. An input voltage selector, such as an F switch, selects between a plurality of input voltages by actuation of a rotatable cam. The output of the input voltage selector is provided as an input to the infinite switch. The rotatable shaft is also operatively coupled to the rotatable cam and thus controls the input voltage selector as well as the infinite switch. The selective provision of two different voltage levels as an input to the infinite switch permits a plurality of simmer voltages when the unit is assembled in an electric range.

Abstract: A control arrangement and method is provided for detecting and responding to disturbances in electrical power systems. In a preferred arrangement, an integration is initiated that is based on a comparison of actual voltage of a source and a reference voltage. When the integration exceeds a predetermined value, the source is considered unreliable. Also in a preferred arrangement, a determination is made as to whether or not the disturbance is a downstream fault condition. For example, this is useful for applications where a transfer is made from a first source to a second source when predetermined disturbances are detected. In this manner, the transfer of the load to a second source is avoided which would continue the supply of the downstream fault. Additionally, the arrangement distinguishes between various degrees of disturbances to permit appropriate response based on the severity and type of disturbance. For example, a first immediate response, i.e.